# How Far Must Mirror M2 Be Moved in Michelson Interferometer?

How far must the mirror M2 of the Michelson interferometer be moved so that 1910 fringes of He-Ne laser light (633 nm) move across a line in the field of view?

The Michelson interferometer is a device that uses the interference of light waves to measure distances and wavelengths. In this question, we are asked to determine how far mirror M2 needs to be moved so that 1910 fringes of He-Ne laser light (with a wavelength of 633 nm) move across a line in the field of view. To find the distance M2 needs to be moved, we can use the formula: Δx = (N * λ) / 2 Where Δx is the distance M2 needs to be moved, N is the number of fringes, and λ is the wavelength of the light. Plugging in the given values, we have: Δx = (1910 * 633 nm) / 2 To calculate this, we need to convert the wavelength from nm to meters: Δx = (1910 * 633 * 10⁻⁹m) / 2 Simplifying this equation gives us the distance M2 needs to be moved. Δx = 0.6068 m Therefore, mirror M2 must be moved approximately 0.6068 meters so that 1910 fringes of the He-Ne laser light (with a wavelength of 633 nm) move across a line in the field of view.

## Calculation for Mirror M2 Movement:

**To find the distance M2 needs to be moved, we use the formula Δx = (N * λ) / 2**, where Δx is the distance M2 needs to be moved, N is the number of fringes, and λ is the wavelength of the light. In this case, N is given as 1910 fringes, and λ is given as 633 nm. First, we need to convert the wavelength from nm to meters by multiplying it by 10⁻⁹. Then, we substitute the values into the formula: Δx = (1910 * 633 * 10⁻⁹ m) / 2. By simplifying the equation, we find that Δx is approximately 0.6068 meters. Therefore, mirror M2 must be moved approximately 0.6068 meters so that 1910 fringes of the He-Ne laser light (with a wavelength of 633 nm) move across a line in the field of view. The mirror M2 of the Michelson interferometer needs to be moved approximately 0.6068 meters so that 1910 fringes of the He-Ne laser light with a wavelength of 633 nm move across a line in the field of view.